In printing mechanism, the print hammer usually is caused to be moved against the record media, in turn against the platen which platen is normally fixed or secured in a precise position to provide a printing line. Alternatively, the hammer may be fixed or secured and the platen may be movable or pivotable to press against the hammer or type wheel or a like type character carrying member.
Representative prior art in the area of movable hammer means or movable platen means is as follows:
U.S. Pat. No. 3,333,670, issued to Z. A. Yazejian et al. on Aug. 1, 1967, discloses a step by step incremental feed mechanism utilizing a linkage train formed of three links connected in a pivotable manner and disposed to be actuated by an actuator.
U.S. Pat. No. 3,693,473, issued to R. W. Beachner on Sept. 26, 1972, discloses a controlled pressure platen wherein the platen is movable through a pair of actuating toggle linkages.
U.S. Pat. No. 3,693,543, issued to H. F. Noller on Sept. 26, 1972, shows imprinting mechanism wherein the die plate is fixed and the platen is movable with a wedge being utilized to vary the platen pressure.
U.S. Pat. No. 3,758,010, issued to P. H. Hamisch on Sept. 11, 1973, discloses printing apparatus wherein a print head assembly is secured to the frame and the platen assembly is pivotally mounted to the frame.
U.S. Pat. No. 3,768,619, issued to R. A. Lewis on Oct. 30, 1973, shows a printing machine wherein certain elements are stacked together and commonly compressed between a linearly closing anvil and piston and wherein a control system regulates the force of the thrust during the printing process with one of a series of flat platens of different thicknesses being selectively used between the anvil and piston.
U.S. Pat. No. 3,804,015, issued to R. H. Colwill on Apr. 16, 1974, discloses a toggle platen unit wherein the platen is rockable on an arcuate work surface.
U.S. Pat. No. 3,842,957, issued to W. G. Wilkin et al. on Oct. 22, 1974, shows a selective marking apparatus including a drive shaft for raising and lowering a piston and wherein the drive shaft actuates the piston in a reciprocating manner and after actuating the piston, the shaft reciprocates independently of the piston.
U.S. Pat. No. 3,878,779, issued to J. G. Clary on Apr. 22, 1975, discloses a squeeze printer having a fixed platen and a combined aligning and movable printing bar.
And, U.S. Pat. No. 3,967,550, issued to R. E. Busch on July 6, 1976, shows a squeeze printer having a fixed type wheel and a movable platen.